I can't see them doing that, because whether a site is using HTTPS is visible to end users, and Google and many others had already spent a lot of time and effort getting them to notice and care. By contrast, end users know nothing about certificate lifetimes, so it would be hard to explain this change to them.
What typically does work for this kind of thing, is finding a hook to artificially rather than technically necessitate it, while not breaking legacy.
For example, while I hate the monopoly that Google has on search, it was incredibly effective when they down-ranked HTTP sites in favour of HTTPs sites.
( In 2014: See https://developers.google.com/search/blog/2014/08/https-as-r... )
Almost overnight, organisations that never gave a shit, suddenly found themselves rushing through the any required tech debt to get SSL certs and HTTPs in place.
It was only after that drove up HTTPs to a critical mass did Google have the confidence to further nudge through bigger warnings in Chrome. ( 2018 ).
Perhaps ChatGPT and has impacted Google's monopoly too much to try again, but they could easily rank results based on certificate validity length and try the same trick again.